diff --git a/docs/playbook.md b/docs/playbook.md
index d7cb0f3ec57428df8afb21380f4551e114905cfb..3811ec51cfa9f376ce6ffc5eb27dd52b39e175b1 100644
--- a/docs/playbook.md
+++ b/docs/playbook.md
@@ -171,3 +171,7 @@ admins:
       - key_handle: "r4wWRHgzJjl..."
         public_key: "04803e4aff4..."
 ```
+
+**NOTE**: the above will work with *pam_u2f* version 1.0.7, but it will *not*
+work with pam_u2f version 1.1.0 due to changes in the output format!
+